Surface development device



1961 w. LIMBERGER 2,997,937

SURFACE DEVELOPMENT DEVICE Filed. Oct. 10, 1958 INVENTOE watt Limbargmr 2,997,937 SURFACE DEVELOPMENT DEVICE Walter Limberger, Hamburg, Germany, assignor to Lumoprint Zindler K.G., Hamburg, Germany Filed Oct. 10, 1958, Ser. No. 766,524 Claims priority, application Germany Oct. 16, 1957 4 Claims. (Cl. 95-94) The invention relates to a surface development device with one or more baths and pairs of pressing and/or conveyor rollers.

In performing a development process it is appropriate to moisten only one surface of the film base. This requirement has previously been met by spraying the developer liquid on the film base for example through nozzles, or by applying it with a brush roller. These known embodiments have considerable disadvantages, in the first place because a completely uniform moisture distribution over the relevant surface cannot be obtained and in the second place because damage to the film base can take place by reason of the effects of non-uniform moisture distribution. Moreover these known devices can be adapted to the developing of film base in sheet form only with difiiculty and via complicated arrangements for feeding the sheet and for performing the process.

The invention overcomes the disadvantages of known devices in that a plurality of elongated guide elements are arranged in a liquid container so that sheet-contacting upper portions of the guide elements lie in the region of the upper surface of the bath liquid which is held at a predetermined level; the film base advanced by the conveyor elements therefore is thus moistened over the whole of its photosensitive surface turned towards the bath liquid by virtue of the afiinity between the liquid and the layer.

In an advantageous construction, the invention provides that the sheet contacting portions lie just above the meniscus of the bath liquid; in another embodiment the parts supporting the film base lie just below the meniscus of the constant-level bath liquid. The invention also contemplates a construction in which the parts carrying the film base lie at the level of the meniscus of the liquid.

In the embodiment in which the portions of the guide elements supporting the film base lie just above or below the liquid meniscus, the distance thereabove or thereunder is limited to a few tenths of a millimeter and, preferably, to two tenths of a millimeter. This distance insures that the side turned towards the bath liquid may be moistened, without permitting liquid to reach the surface of the film base turned away from the bath.

The guide elements consist, for example, of bars fixed on the floor of the bath, of which the upper ends lie at the meniscus of the liquid in the bath. In a particularly advantageous construction the guide elements are formed as beads, preferably in the bath-container floor, whose apices lie in the vicinity of the liquid meniscus and, advantageously, precisely at the meniscus of the liquid. The guide elements formed as beads may be provided with undulating upper edges of which the highest portions project from the liquid and the low-lying parts lie in the plane of the liquid meniscus or therebelow. The construction of the guide elements in which only parts orsections thereof lie in or above the level of the liquid in the bath has the advantage that the uniform moistening of the photosensitive surface is improved by the wetting between the individual guide elements efiecting the process. This construction is however only advantageous for use with film bases with some rigidity. For the treatment of liexible film bases a continuous run of guide elements is provided just above the liquid meniscus. Again the complete moistening of the layer is insured because of the paral elism between the liquid and the layer so that guide States Patent Patented Aug. 29, 1961 elements may also be provided with sheet-contacting portions below the level of the liquid.

The guide elements may run parallel or may be inclined to the feed direction of the film base. The inclined configuration of the aforementioned beads permits the division of the bath container into successively arranged individual tanks which can be filled with different treatment liquids.

For securing a precise liquid level or meniscus there is provided in an advantageous embodiment of the invention a plug, supply stopcock or injector as is well known per se.

The invention further envisages in one constructional form the conveying of the film base obliquely to the liquid surface or to the bearing elements. To this end there can advantageously be provided at the incoming side of the bath conducting elements in the form of co-operating rollers, which advance the forward edge of the film base to the liquid surface and to the first guide element.

The construction according to the invention has the advantage that the film base is carried across the liquid without any mechanical stressing.

The above objects, features and advantages of the invention will become more readily apparent from the following description of an illustrative example, reference being made to the accompanying drawing in which:

FIG. 1 is a section along the direction of feed of a film base through an apparatus with two bath containers; and

FIG. 2 is a section along the line lI-II of FIGURE 1.

In the apparatus shown in FIGURE 1, two tanks 10 and 11 are provided, of which for example the tank 10 contains developing liquid and the tank 11 contains fixing liquid. The tanks lie one after the other in the direction in which a film base is fed. In this embodiment the guide elements (as is to be seen in FIGURE 2) are constituted by beads 12 formed in the tank floors, which run in the longitudinal direction of the tank, i.e. parallel to the feed direction of the film base. It is to be noted that in this construction connecting openings beneath the level of the liquid are provided between the wall sections between individual beads, so that the liquid is held at the same level throughout the tank. The upper edges of the beads 12 lie precisely in the plane of the liquid level, so that the film base sliding on the beads 12 over the liquid surface and overflow over the forward edge is securely excluded.

At their sides the tanks 10 and 11 have reservoirs 13 and 14 respectively, which serve to maintain a constant liquid level in the tanks 10 and 11. These containers 13 and 14 are closed on all sides and are connected with the associated tanks 10, 11 only through tubes 15 and 16 respectively. These tubes 15, 16 are led to the appropriate tanks 10, 11 and are bent downwardly at their ends, so that the tube months 17 and 18 lie in the same plane as the liquid level in the tanks 10, 11.

The tanks 10, 11 are formed from the material of the lower part of the housing 39 of the apparatus shown in FIGS. 1 and 2. This lower part of the housing can consist, for example, of lead or plastic material and is covered by a lid 38.

At the face of the lower part of the housing 39 is provided an inlet slit 19 for introducing the film base. An inlet support plate 20 is arranged at the foot of said slit, while the opposite wall of the apparatus is provided with an outlet slit 21 having a receiving table 22.

Behind the introduction slit 19 I provide a pair of conveyor rollers 23 and 24 positioned so that a film base fed through the slit 19 is drawn between the rollers 23 and 24. The upper roller 24 is displaced from the vertical plane through the axis of the shaft of roller 23 in the direction of the bath 10, so that the line 25 connecting the centers of the rollers is offset from the vertical with its upper end d inclined toward the tank 10. As a consequence of this arrangement a film base conveyed between the rollers 23, 24- receives a feed direction perpendicular to the line 25.

The roller pair 23, 24 is so arranged with respect to the tank It) that the film base conveyed between the roller pair 23, 24 slides over the upper-edge 26 of the tank toward the liquid surface in the tank lfi. After the film base has passed over the forward edge 26 it moves over the guide elements 12, located in the tank 10, which run parallel to the liquid meniscus and which convey the film base in this direction in continuation of the feeding motion. c t s t a Further in the transport direction ofthe film base, behind the tank 10', another pair, .rollers 27, 2,8;.are provided at such height that the film base issuing from .the bath 1% passes between the rollers 27 and 28. The rollers 27 and 2S serve not only to transportctheifilm base but also to squeeze the liquid out of it. Thisliquid drips into a containers 29 beneath the roller pair 27, 28 in the lower part of the housing 39'. t

The tank 11 is located in the feed direction of the film base behind the roller pair 27, 28. The rollers 27, 28 are positioned in the same manner as rollers 23, 24-, so that the connecting line 30 between the roller axes is inclined and the film base carried between the rollers is conveyed to the meniscus of the liquid in the tank 11. A further pair of rollers 31, 32 is arranged rearwardly of the tank 11. This roller pair lies just forwardly of the outlet slit 21 and serves to convey the film base and also to press out the liquid it holds; the liquid runs into a chamber 33 provided in the lower part of the housing 39.

The roller pairs 23, 24; 27, 28; and 31, 32 are driven, for example, by means of a chain drive 34 whose driving motor is designated 35. The rollers of each of the individual roller pairs are interconnected for complementary rotation one with the other, for example by means of gear wheels. In FIGURE 4 the gear wheels 36, 37 of the respective rollers 23, 24 are shown. By this drive a uniform feeding of the film base through the device is obtained.

In the treatment of sheets, film bases are used of a greater length than the distance between the two roller pairs 23, 24 and 27, 28, so that the forward end of a film base is engaged, for example, by the roller pair 27, 28 before its rear end runs through the roller pair 23, 24.

What I claim is:

1. A device for developing flexible sheets having a photosensitive surface, comprising a container adapted to hold a developer liquid, a plurality of elongated guide elements in said container, said elements having sheet-contacting upper portions substantially at the level of said liquid, means for maintaining a constant liquid level in said container, and drive means adapted to deposit one of said sheets onto the surface of said liquidand to move each sheet along the liquid surface withnits photosensitive surface facing downwardly; said drive means comprising a pair of contacting, oppositely rotating rollers adapted successively to pass said sheets therebetween, the centers of said rollers being interconnected by a line slightly inclined to the vertical so that a plane tangent to both of said rollers at their point of contact slopes downwardly at a small acute angle to the horizontal whereby each sheet gradually approaches with its photosensitive surface the surface of said liquid at said acute angle before coming into contact with said guide elements; said guide elements extending substantially parallel to the direction of travel of said sheets over the full length of the container and with a mutual separation corresponding to asmall fraction of the transverse dimension of said container.

2. A device for developing flexible sheets having a photosensitive surface, comprising two closely spaced containers adapted to hold respective processing liquids, said container being provided with entrance and exit edges projecting above the liquid level, a plurality of elongated guide elements spacedly extending in each oftsaid containers from the entrance edgeto the exit edge thereof with a mutual separation corresponding to a small fraction of the transverse containerv dimension, said elements having sheet-contacting upper portions substantially at the levels of the liquids in said containers, means for maintaining constant said levels, and drive means adapted successively to deposit each of said sheets upon the surface of the liquid in each of said containers with the photosensitive surface of the sheet facing downwardly; said drive means comprising a first and a second pair of contacting, oppositely rotating rollers each positioned immediately ahead of a respective one of said containers, the centers of the rollers of each of said pairs being interconnected by a line slightly inclined to the vertical so that a plane tangent to both of the rollers of each of said pairs at their point of contact passes just above the entrance edge of the respective container and slopes downwardly at a small acute angle to the horizontal whereby each sheet is supported on said entrance edge as it gradually approaches with its photosensitive surface the surface of the liquid in the next-following container before coming into contact with the guide elements thereof, said second pair of rollers being positioned close enough to the exit edge of the first container to receive the leading edge of each sheet coming across the exit edge thereof.

3. A device for developing flexible sheets having a photosensitive surface, comprising a container adapted to hold a developer liquid, means for maintaining a constant liquid level in said container, drive means adapted successively to deposit each one .of said sheets onto the surface of said liquid and to move said sheet along the liquid surface with its photosensitive surface facing downwardly; said drive means comprising a pair of contacting, oppositely rotating rollers adapted to pass said sheet therebetween, the centers ofsaid rollers being interconnected by a line slightly inclined to the vertical so that a plane tangent to both of said rollers at their point of contact slopes downwardly at a small acute angle to the horizontal whereby each sheet gradually approaches with its photosensitive surface the surface of said liquid; and a plurality of transversely spaced elongated guide elements extending at least partly submerged within said container over its full length in the direction of sheet travel and with a mutual separation corresponding to a small fraction of the transverse container dimension, substantially at the liquid level, for limiting the penetration of the liquidby said sheet.

4. A device according to claim 3 wherein said container has 'a liquid-confining wall provided with a proximal portion projecting above the liquid level to a level lying substantially on said sloping plane, thereby forming a rest for the sheet on its passage from said rollers to the liquid surface.

References Cited in the file of this patent UNITED STATES PATENTS 717,021 Pollak Dec. 30, 1902 1,348,029 Mason July 27, 1920 1,624,781 Dye Apr. 12, 1927 2,337,864 Beidler Dec. 28, 1943 

